This invention relates to computer input devices, in particular to keyboards. A computer keyboard generally comprises a plurality of keys mounted on a substantially horizontal panel, for entering commands and data units (i.e., characters) into a computer or computer display terminal. Each key is mechanically engaged with a binary switch (i.e., on-off switch) configuring a switch array that is periodically scanned by an electronic circuit to sense the key's status and transmit a corresponding code (called scan code) to a computer system, when a change in the switch array status is detected.
This invention relates to a new computer keyboard comprising additional non-binary means to improve the working condition of a keyboard operator and accelerate some tasks during operation of computer programs.
Computer keyboards are used in almost any kind of computer application. Compared to other computer peripherals, computer keyboards have not evolved significantly from the first specimen up to the present state of the art, the only changes being limited to varying key layouts and modifications in key shapes and switching mechanisms. At the time of the present invention, we know of no significant keyboard improvements on operational features or functional enhancements.
Computer keyboards generally include: a first group of alphanumeric keys, used for entering textual, numeric and punctuation data, a second group of keys generally called "control keys", used for controlling some program functions implemented in most of the contemporary programs (e.g., HOME, END, PAGE UP, DELETE, etc.), a third group comprising general purpose keys, also known as "function keys" (generally labeled F1, F2, F3, etc.) and a fourth group comprising a set of four keys generally called "arrow keys", generally used to select an item from a list, control a cursor's position, etc. In almost all computer keyboards, a special control key generally labeled "ENTER" is also provided, usually used to communicate the computer that a certain data entry or control task is completed.
In normal operation of a computer keyboard, communication between operator and machine comprises tasks that may be grouped in two main groups:
1. Data entry tasks, and PA1 2. Control and command tasks.
In operating many contemporary programs using a computer keyboard, a significant portion of the tasks included in the second group require intensive use of a certain group of keys, generally in a repetitive fashion, in bursts of repeated activation of a single key. This group of keys mainly comprises the arrow keys, and secondly the control and function keys. Moreover, the repetitive bursts generally appear as a sequence of several bursts of repeated activation of keys that have functions inverse to each other (e.g., PAGE UP/PAGE DOWN, ARROW LEFT/ARROW RIGHT, SPACE FORWARD/BACK SPACE, etc.), usually within a successive approximation to a final state.
This phenomenon may be observed in almost any kind of modern computer application, but mainly in highly interactive applications running in personal computers, like programming, text editing, spreadsheet editing, etc. This is primarily because user interfaces had evolved from command line keyword oriented interfaces to more friendly, visual feedback interfaces controlled by a limited group of keys (or alternatively by another kind of computer input device e.g., a mouse).
For example, in former editing applications, a special screen area was assigned to enter program commands by typing one or more keywords in it. However, contemporary editing applications tend to use a single key to switch a main menu displaying all available command options, and a particular command can be selected by typing the arrow keys repeatedly until a desired option is highlighted. This interface concept has been almost uniformly adopted in the software industry.
On the other hand, when tasks included in the first group are performed, this phenomenon is not as frequent, because the statistical distribution of alphanumeric keystrokes in most applications is substantially constant so that the probability of repeated keystrokes of the same key is far lower.
We have also observed that repeated activation of the same key in a computer keyboard causes an uncomfortable tension in the operator's hands and wrists that frequently causes fatigue in the operator and results in productivity loss. It is believed that this tension excess is due to the lack of movement compensation between fingers and other parts of the hand when performing repetitive typing. This belief is supported by the fact that this tension does not appear when typing for example a piece of text, which normally has a relatively constant letter probability function.
A widely used approach for this problem is the auto-repeat method (generally called "typematic") implemented in almost all computer keyboard application. The auto-repeat method consists in automatically repeating the scan code corresponding to the key being pressed at a fixed rate, when the key is kept pressed at least for a pre-determined time period.
Although it represents an improvement, significant enough for it to become widely accepted, this method is not all that comfortable and efficient, mainly because the auto-repeat rate is given by a fixed time reference and hence it is not capable of providing speed and precision simultaneously. That is, a high auto-repeat rate sacrifices precision and a low one gives good precision but is slow. This unavoidable speed-precision trade-off leads the operator back to repetitive typing because usually it is the only way to get enough precision in most tasks. Moreover, throughout a certain computer operation session, different auto-repeat velocities are needed depending on the particular task being performed; this is a requirement not satisfied by the auto-repeat method which lacks this flexibility. Still another disadvantage of the auto-repeat method is that the initial period preceding the auto-repetition function produces some uncertainty in the number of repetitions generated. This is because if the delay is too short it may produce undesired keystrokes, and if it is too large, it produces an uncertainty about the instant in which the repetition will begin, reducing the chances of precise control even more.
This accumulation of effects leads average keyboard operators to perform, or at least complete, a lot of operation with repetitive typing, since it appears as mentally less distressing although, in the long run, it strains one physically and psychologically, perhaps unconsciously.
Consequently, there is a need of an improved computer keyboard, capable of performing this kind of operations more efficiently, to improve the work conditions of a computer keyboard operator and enhance productivity.